Radio dial construction



March 23, 1937.

J. DREYFUS RADIO DIAL CONSTRUCTION Filed Dec. 26, 1955 OY M mmM Patented Mar. 23, 1937 PATENT OFFICE RADIO DIAL CONSTRUCTION Jean Dreyfus, Paris, France Application December 26, 1935, Serial No. 56,206 In France January 16, 1935 11 Claims.

The present invention relates to radio dials and more particularly to a combined tuning dial and loud speaker for radio receiving sets. The loud speakers for electric reproduction of acoustic vibrations usually have a diaphragm with a large vibrating surface.

An object of the present invention is to utilize the loud speaker diaphragm as a support for figures, images or indicia of any desired character and for any desired purpose. There are many cases where such a combination results in great saving of space and costs of the apparatus as will be understood. The figures, images or indicia of the desired shape and configuration may be applied to the diaphragm surface by means of a suitable coloring material in accordance with any one of the well known reproducing processes in the art, such as by a typographic, photographic or engraving process, and the like. As is understood, care must be taken not to damage and impair the acoustic properties of the diaphragm.

The invention has special application for radio receivers equipped with a loud speaker and a tuning dial serving for indicating the transmitting station to which the receiver is tuned. In the latter case, the tuning indicia such as a wave length scale or scale indicating the station names or call letters are directly applied to the loud speaker diaphragm serving as the tuning dial. A suitable index member such as a pointer which may be either mechanical or optical is arranged to move over the diaphragm-dial sur-- face in accordance with the adjustment of a variable tuning element such as a variable tuning condenser to indicate the station or wave length to which the set is tuned.

Further objects and advantages of the invention will become more apparent from the follow. ing detailed description taken with reference to the accompanying drawing in which I have 11- lustrated one form of embodiment of a combined loud speaker and tuning dial.

In the drawing wherein similar reference numerals identify similar parts:

Fig. 1 shows a cross-section of a combined tuning dial and loud speaker structure according to the invention; and Fig. 2 is a front view of Fig. 1.

Referring more particularly to the drawing, I have shown at l, a casing or cabinet for housing a radio set comprising substantially a chassis 2 upon which are mounted the individual parts of the set such as tubes, coils etc. and a loud speaker mounted with its orifice directed to ward the front wall of the cabinet I in a known manner. The parts of the radio receiver not necessary for the understanding of the invention have been omitted for the sake of simplicity of illustration. Item 3 represents a variable condenser serving as a tuning element v and mounted upon the chassis 2. The condenser may consist of the usual stationary set of plates co-operating with a set of movable plates mounted upon a shaft 4 which may be rotated by operating an adjusting knob shown at 5 for tuning the receiver to a desired transmitting station.

The loud speaker shown is of the electro-dynamic type comprising a cup-shaped magnet with a central core 7 and an annular pole piece 8 to secure an annular air-gap within which is arranged a voice coil 9 wound upon a cylindrical extension of conical diaphragm shown at It). The latter is mounted to the front wall of the casing'l with a bafile ring l2 interposed therebetween in accordance with well known loud speaker constructions. Further constructional details of the loud speaker have been omitted as they are well known and are outside the scope of and not essential forunderstanding of the invention.

Item II shows the exciting coil for the loud speaker wound round the core 1 in a known manner and serving to produce a constant magnetic biasing field.

In accordance with the present invention, the surface of the loud speaker cone I0 is provided with one or more tuning scales such as shown more clearly in Fig. 2. In the latter, 3 concentric scales are shown covering separate wave length ranges such as the regular broadcast range from 500 to 1600 kilocycles, police call and similar signals from about 2000 to 6000 kilocycles, and the international short wave broadcast range from 6 to 20 megacycles. Item l3 represents a pointer arranged to move over the diaphragm in accordance with the adjustment of the tuning condenser by operating the adjustment knob 5. For this purpose the pointer I3 is mounted upon a shaft l4 passing through a perforation of the core I and connected with the shaft t of the tuning condensers 3 through a suitable mechanism such as a wire and pulley drive comprising pulleys 6 and I5 and the wire or cord l6. Since the diaphragm 10 consists usually of paper or similar darkly colored material, it is preferable to apply the tuning indicia in a light color, preferably in white or silver color by means of a suitable reproduction process such as a photographic, typographic or engraving process.

If the diaphragm is produced from a fiat sheet, the impression of the tuning indicia may be made in the fiat condition of the sheet. If the diaphragm is produced by a molding process, the impressions may be applied during the molding by using a suitable conical mold. In order to improve the visibility of the diaphragm-dial or to control its visibility when desired, I have shown an illumination system comprising in the example illustrated a lamp l8 carried by the shaft l4 and provided with a reflector to concentrate its light upon the dial surface. The orifice of the loud speaker may be covered with a cloth H or similar sound pervious material of variable transparency in such a manner as to be opaque normally and to become sufiiciently transparent when the lamp i8 is lit during the operation of the receiver to render the tuning dialand the indicia thereon visible to the operator. Since those parts of the dial or cone of the loud speaker enclosed by the angular positions a, b of the pointer l3 as shown in Fig. 2 are badly visible due to the inclination in a backward and downward direction of this portion of the diaphragm, it is preferable to leave this part free from any tuning indicia and utilize only the remaining portion of the diaphragm as a dial surface.

As is evident, the embodiment of the invention as shown in the drawing has been chosen for illustration only and it will be understood that many variations may be made of the arrangements and design of the parts and elements differing from the specific construction illustrated. Thus for instance, the diaphragm of the loud speaker may be inverted; that is, the tuning indicia may be applied to the convex surface in place of the concave surface as shown in the illustration. It is further understood that any type of loud speaker may be used such as an electro-dynamic speaker, a speaker with a permanent magnet, or an electrostatic speaker. It is further understood that the diaphragm need not have a conical shape but may be flat or spherical or have any other form and that it may consist of any suitable material such as paper, metal, etc. The illumination system can also be varied in such a manner as to discriminate between the separatewave bands and the pointer l3 can be replaced by an optical pointer projecting a luminous line or streak or any other index of desired shape, such as an arrow, etc., upon the dial surface. Thus for instance, the lamp 18 may be totally covered with the exception of a small slit through which a narrow beam is projected upon the dial producing a luminous line or streak cooperating as a movable index member with the tuning scales.

It is further understood and to be regarded as coming within the scope of the invention, that the diaphragm may serve to carry any other signs or images such as a clock dial or a geographical map, landscape, portrait and the like. Furthermore, the diaphragm of the loud speaker may be of transparent material such as of celluloid and illuminated from behind so as to render the tuning scales visible by trans-illumination. Finally, it will be understood that the loud speaker may be embodied in any other type of apparatus such as in a phonograph or television apparatus or may be used separately and independently.

As is evident from the above, many further variations and modifications as well as applications of my invention may be made, all coming within the broader scope and spirit thereof as defined in the appended claims.

I claim:

1. In combination with a radio receiver a loud speaker having a diaphragm, the sound emitting portion of said diaphragm carrying tuning indicia, and index means operated by a variable tuning element of said receiver co-opcrating therewith to indicate the transmitting station to which said receiver is tuned.

2. In combination with a radio receiver, a loud speaker having a vibratory diaphragm of extended surface, the sound emitting portion of said diaphragm carrying tuning indicia, and an indicating pointer arranged to move over said diaphragm in accordance with the movement of a variable tuning device of said receiver to indicate the transmitting station to which said receiver is tuned.

3. In combination with a radio receiver, a loud speaker having a conical shaped diaphragm, the concave sound emitting portion of said diaphragm carrying tuning indicia, and a movable pointer adapted to move over said diaphragm in accordance with the movement of a variable tuning device of said receiver to indicate the transmitting station to which said receiver is tuned.

4. In combination with a radio receiver, a loud speaker having a diaphragm, said diaphragm carrying a tuning scale, a shaft arranged concentrically to said diaphragm, a pointer cooperating with said scale carried by said shaft, means for rotating said shaft in accordance with the movement of a variable tuning device of said receiver to indicate the transmitting station to which said receiver is tuned.

5. In combination with a radio receiver, a loud. speaker having a diaphragm, the sound emitting portion of said diaphragm carrying tuning indicia,

an indicating pointer adapted to move over said diaphragm in accordance with the movement of a variable tuning device of said receiver and illuminating means for rendering visible said tuning indicia during the operation of said receiver.

6. In combination with a radio receiver, a conical shaped diaphragm, the sound emitting portion of said diaphragm having tuning indicia applied to its concave surface, a pointer co-operating with said tuning indicia adapted to move over said diaphragm in accordance with the movement of a variable tuning device of said receiver, and illuminating means for rendering said tuning indicia visible during the operation of said receiver.

'7. In combination with a radio receiver, a conical shaped diaphragm, said diaphragm having tuning indicia applied to its concave surface, an indicating pointer co-operating with said tuning indicia and adapted to move over said surface in accordance with the movement of a variable tuning device of said receiver, a source of light for illuminating said surface during the operation of said receiver, and a sound pervious cover for said diaphragm adapted to normally conceal said diaphragm and to reveal the tuning indicia thereon when illuminated by said source.

8. A radio receiver as claimed in claim '7 including reflecting means for concentrating the light from said source upon said tuning indicia.

9. A radio receiver as claimed in claim 7 in which said loud speaker surface is of darker color as compared to the color of the tuning indicia applied thereon.

10. In a radio receiver, a cabinet, a loud speaker therein, a diaphragm for said loud speaker having its edge portion secured to an opening in said cabinet, the inner vibrating portion of said diaphragm having tuning indicia thereon, movable index means cooperating with said tuning indicia to indicate the station to which the receiver is tuned, a source of light for illuminating said diaphragm, and a sound pervious cover secured to said opening adapted to normally conceal said diaphragm and to reveal the tuning indicia when illuminated by said source.

11. In a radio receiver, a cabinet, a loud speaker phragm and to reveal the tuning indicia when 0 illuminated by said source.

JEAN DREYFUS. 

